Removing copper salts from alkaline liquors.



t e following is a specification.

RUDOLF LINKMEYER, OF BRUSSELS, BELGIUM.

REMOVING COPPER sAnTs snout ALKALINE Lmuons.

'n lseeen.

Specification of, Letters Patent.

latented Sept, 17, 1907.

Application filed March 22i1906. Serial N9- 307,406.

To all whom it may concern: v r Be it'known that I, RUDOLF LINKMEYER, a bj of the Emperor of Germany, residing at Brussels, Bell gium, have invented new and useful Improvem ents in the Removal of Copper Salts by Cellulose, of 'which In the manufacture of'silk-like threads by means of atsolution of cellulose in ammoniacal oxid of copper salts; when'an alkaline bath is employed as'precipitaut a portion of the copper salts sorbed by the alkaline lye.

In order that the process may be commercially m:

v t'ica'ble it is essential thatrthe reagents" employed,

' usually caustic soda, shall be economically recuperated because the precipitation of the cellulose necessitates I relatively large'qiuantities of alkalies, and the alkaline lye owing to the copper salts that dissolves therein,

' assumes a blue tint which speedily becomes so deep that the attendant can no longer follow in the midst of the liquid the threads issuing from the fine openings through which the cupraminjonium cellulose is forced into the alkaliiie lye. Although the reagent is far from being exhausted at this moment, the work can not he proceeded with without renewing the solution unless the copper can be extracted. On the other hand the copper salts cannot be recupcrated. merely by ebullition of the solution and if the free alkali soda t r instance is previously neutralized the process becomes too expensive, the soda being completely lost.

In accordance with the present invention the copper is ektracted in a very simple manner and so that it is even able to reenter the cycle of operations directly. The process consists in eliminating the copper salts from the alkaline lye by means of cellulose which is merely plunged into the bath. Either cotton or wood of the solution is ab-' pulp or any kind of cellulosic material will answer.

The salts of copper are deposited thereon completelyand at the sametime a large portion of the ammonia absorbed by the alkaline lye; the cellulose assumes an increasingly blue tint while the lye becomes de colorized very rapidly and may be reemployed for the v precipitation .of the cupro-ammoniacal solution.

The fiber charged with copper salts may be regen erated by dissolving the copper salts and the ammonia that it contains in an appropriate acid dered industrial'and practical, or it may be used directly for making fresh quantities of cuprammonium cellulose,- after making allowance for the copper salts that have remained in the threads. The amount of copper deposited on the fiber isnot sufficient for making a fresh solution of cellulose by adding. only the necessary ammonia. Some of the copper contained in the previous solution having remained in the. threads made out of the solution, a corresponding amount must be added to supplement that which has been removed by the fiber in order to make up for the deficiency.

What I claim as my invention and desire to secure by Letters Patent is:

In the manufacture of srtificlulsilk from cuprammonium cellulose, the process of removing,' copper from they residual caustic alkaline liquors which consists in immerslng bundles of vegetable fibers therein until the copper has deposited thereon and removing them, together with the :ldherlngcopper salts.

in testimony whereof I have aflixed my signature in presence of two subscribing witnesses.

RUDOLF LINKMEYER;

I Witnesses A. J. E. KIRKPATRICK, A. O. VOGEL.

. 45 The direct precipitation by the alkaliesis thus ren 

